To begin with we need to understand how new products are adopted (used) by different parts of society. Think about any piece of technology as an example, how long do you think it'll take for your parents to be on TikTok? and then how long until your grandparents? This concept is called the Diffusion of Innovation
Entrepreneurs need to gather a lot of opinions in order to figure out which way to go, getting advice is a core part of the whole journey. However, when you are doing entrepreneurship you are walking into the fog of the unknown and this means that you (1) need to take small steps and (2) ensure you are not being led down the wrong path. The only way to ensure you are heading down the right path is to stay close to your early adopters and later your users more generally.
This section of the library is all about the best practices of engaging with your users, whether it be interviewing, observing them use your product, empathy mapping or any number of other ways.